(da)sh substring matching speed tests

substrcmp() {
    local x y z
    x=${#1}; y=${1#*$2}; z=${#y}
    [ $x -ne $z ]
}



date --rfc-3339=ns
for i in $(seq 1 20000); do
    echo "abc${i}def%Fzyx" | grep -Fqe '%F'
done
date --rfc-3339=ns

# 2018-04-19 00:39:20.956273584
# 2018-04-19 00:39:36.707469684



date --rfc-3339=ns
for i in $(seq 1 20000); do
    substrcmp "abc${i}def%Fzyx" '%F'
done
date --rfc-3339=ns

# 2018-04-19 00:39:20.863260849
# 2018-04-19 00:39:20.955660959



date --rfc-3339=ns
for i in $(seq 1 2000); do
    echo "abc${i}def%Fzyx" | grep -Fqe '%F'
done
date --rfc-3339=ns

# 2018-04-19 00:40:49.657582863
# 2018-04-19 00:40:51.202037260



date --rfc-3339=ns
for i in $(seq 1 2000); do
    substrcmp "abc${i}def%Fzyx" '%F'
done
date --rfc-3339=ns

# 2018-04-19 00:40:49.647043516
# 2018-04-19 00:40:49.656980633